Our school has an NXTCam on order, and we are looking to use it in RoboCup Junior rescue to find the pesky green men.

We have looked at NXTCamView, and setting the colours up etc shouldn't be too hard. However, the programming seems slightly more advanced than we are used to.

We need the robot (which will have a 70-90 degree downwards facing NXTCam) to detect the green on a track, which will be navigated by 3 light sensors pointing down to follow a black line round a course. The light sensors work fine at detecting the black and silver, but green, with its likeness at reflecting light like black, is indistinguishable. Even with the HiTechnic Color Sensor we cannot detect it.

So we need to detect green and hopefully silver targets along the track. If you could help us with some code, we would be grateful.

PS. The robot does not need to follow the green man, merely to detect it when it is in the centre or lower of the frame.

I suggest looking at the RobotC code that has been provided on the mindsensors website, it is a good driver and source files are good to learn from. I also have my modified driver for the NXTcam if you are interested, its very similar to the one on the mindsensors page but I added functions to display the blobs easily on the NXT screen, nice for debugging and understanding what is going on.

Yes, you probably need to play with the Cam view first to ensure it can distinguish between the dark green and black accurately and reliably before dedicating the time in the code. docilio is correct. Dark green under shade...(like people's shadow, or for the fact that it may be in the lower floor of the platform), you can easily misidentify it as the black line. It then turns out to be no difference in using this vs. color sensor. the only difference will be $150 vs $60.

You will probably have to create some special algorithm like a suspected green vic code. Honestly, talkiing about a real life simulation. It would be like you, as a human rescuer, saw some objects seemingly to be victims, but cannot quite see it. Now, how do you make the right decision? Should you proceed as there are many more victims you need to save in a restrained time frame? Or should you just spend more time just to stay at the same sport to analyze whether it is really a victim? Or perhaps, I, as a human rescuer, will remember there was a supicisous spot that I must go back if I still have time left= after I have saved all others!!! Almost a life lesson instead of technical!

I love the RCJ game a lot more than FLL, or FRC. FLL field is 100% predefined and does not give you much information from its environment so you have to use dead reckoning most of the time. Then, FRC, mostly mechanical. If you are into mechanical engineering, FRC IS wonderful. However, if you are into building intelligence software, RCJ is great!

_________________==Elizabeth Mabrey

Thu Feb 05, 2009 10:09 am

vnguyen

Site Admin

Joined: Wed Jan 24, 2007 10:44 amPosts: 442Location: Pittsburgh, PA

Re: NXTCam usage in RCJ

Moved to RCJ forum.

_________________Vu NguyenSoftware Training Development Team | WebmasterNeed more support? Email ROBOTC Support at support@robotc.net to put in a support ticket

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